Thursday, November 1, 2012

Nate Silver's Life Shows Us How Politics Are Like Baseball

Nate Silver, of the oft-mentioned FiveThirtyEight blog where he offers statistical analysis of this year's political races, has recently come under attack for being, well, statistically-minded.

The creator of the PECOTA system, one which analyzes baseball players to track and predict their performance over a given season, Silver has applied similar analysis of polling data, demographic data, and a host of other factors, into a system to gauge the outcomes of this year's elections—and not just the Presidential race, in which he forecasts a 76% chance of Barack Obama winning re-election. In Arizona, he's predicting a 74% chance for Republican Jeff Flake to overcome Democrat Richard Carmona in this year's U.S. Senate race; Mitt Romney has a 97% chance of pulling out the win in the Presidential race here.

But as a result of this statistical analysis, Silver is catching flak from political pundits...much in the same way he was attacked for his PECOTA system by sportswriters — which is what Deadspin.com writer David Roher covers in this fantastic feature-length piece currently hosted on Deadspin's emergency downtime site (Gawker Media sites are still down as a result of the effects from Hurricane-turned-Superstorm Sandy).

Here's an excerpt, though I thoroughly recommend you read the full piece, which you can find here:

With the election just a few days away, analysis based on state poll aggregation—Silver’s included—suggests that Barack Obama is a heavy favorite against Mitt Romney. The president holds a slight but strong lead in key electoral states. This doesn’t sit well with many political pundits, who insist that the outcome is anyone’s guess and headed down to the wire. Many of these people have directed their anger toward Silver, whose New York Times-hosted blog has predicted a strong probability of an Obama victory since June. They insist he is biased or sloppy in his methodology, even though they seem unaware of how he makes his predictions and of statistical analysis in general. They say—and I’m not kidding—he’s too gay for this sort of work.

In retrospect, we should’ve seen it coming. It was only a matter of time before the war on expertise spilled over into the cells of Nate Silver’s spreadsheets. In fact, in some ways it had already. Turns out that nothing could have prepared Silver better for the slings and arrows of a surly and willfully obtuse pundit class than working on the fringes of sportswriting over the past decade.

Silver became well-known among baseball statisticians in 2003, when he debuted his PECOTA projection system on Baseball Prospectus. While other projection systems already existed, PECOTA had two key strengths: It based its player projections on the past performances of similar players, and it gave a probability distribution for each player to reflect the uncertainty of the measurement. For example, if a hitter battled an injury through the season and his production suffered, he’d hit his 20th-percentile PECOTA projection rather than miss the mark entirely. Some players are harder to project than others, and Silver’s methodology let the reader in on his relative confidence. None of this was unique to baseball; scouts have always relied on player archetypes, and front offices have always understood that production tends to fall within an expected range rather than on a straight line. All Silver was doing was taking that analysis out of the realm of the gut.